Question about ribcase trans and clutches

[Sarastro]

I have a 1960 bugeye sprite, largely stock except for a "ribcase" transmission. I don't know much about these, so a few questions:

1. Where did they come from? Some later model? If so, which ones had this transmission as a standard item?

2. Is the installation of one of these on an older car simply a bolt-on replacement? Or, are any clutch changes necessary?

3. In what way are they superior to the original, smooth-case transmission?

4. Do they have the same gear ratios as the original, smooth case unit?

This seems to be one of those things where everyone (except me!) knows all about them, but I can't find much in print to answer these questions. If anyone feels like taking the time to educate me, I'd be very grateful.

 

[Bugeye58]

Steve, the rib case came out in the '63 models, and continued until the 1500 Midgets, which had the Spit engine and tranny.

They are pretty much a bolt in, but if you want to couple one to a 948, you either have to use a 1098 or 1275 back plate, or do some creative grinding to the 948 plate.

They have closer gear ratios, and a different, easier to service synchro setup. Parts are easier to get for the rib case, other than the input shaft assembly, which has been difficult to find for quite awhile.
A worthwhile replacement for the old smooth case, in my estimation.
Jeff

 

[Sarastro]

Thanks for the info. I suspect mine must have the 1098 plate, since I see no sign of grinding, at least from the outside.

I take it the the standard, 948+smoothcase clutch can be used, too, then?

 

[jlaird]

I know the difference between a 1275 backing plate, no oil pump cover I think.

What is the difference on the 1098 one?

Or am I just all wet as usual. That's fuel dripping from my fingers.

 

[Bugeye58]

Jack, the 948 backplate is a thinner item, with a rolled edge around it. This edge hits the bellhousing on a ribcase. 1098/1275 plates are thicker, and have a flat surface on both sides. They all have the "tuna can" oil pump cover.
Jeff

 

[jlaird]

Oh, thanks Jeff. Hay, I have a brand new tuna can oil pump for a 948 that will not fit under the can. Otherwise it is new and never been used. It looks right, is just too big.

 

[fmichaels]

you know, after disassembling three trannies, i have realized that when someone says "the gears look good" doesn't really mean they looked at the right gears at all. i found that you have to remove the shifting forks to see the real damage and it's not always easy (but definitely necessary) to look at the laygear and reverse gear both of which are at the bottom of the case. so the next time someone tells you the gears look good (a boilerplate statement on ebay) remember buyer beware! all these trannies look pretty good with the access cover removed.

 

[Ohiobugeye]

Good information, I wasn't aware that a rib case would not bolt up to a 948 without the back plate modification. Learn something every day........keeps the mind working.

 

[zimmy]

my tranny looked nice till i disassembled it and noticed 1st gear had no teeth left!...haha
u really gotta know what ur lookin for in there.....z

 

[fmichaels]

zimmy .. they were in a cup next to the bed!